<template>
  <div>
    <router-link
      to="/"
      tag="div"
      class="header-abs"
      v-show="showAbs"
    >
      <div class="iconfont header-abs-back">
        &#xe624;
      </div>
    </router-link>
    <div class="header-fixed"
         v-show="!showAbs"
         :style="opacityStyle">
      <router-link to="/">
        <div class="iconfont header-fixed-back">
          &#xe624;
        </div>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
  export default {
    name: "DetailHeader",
    data() {
      return {
        showAbs: true,
        opacityStyle:{
          opacity:0
        }
      }
    },
    methods:{
      handleScroll (){
        console.log("执行")
        const top = document.documentElement.scrollTop
        if (top >60){
          let opacity = top / 140
          opacity = opacity > 1 ? 1 : opacity
          this.opacityStyle = { opacity }
          this.showAbs = false
        } else {
          this.showAbs = true
        }
      }
    },
    activated() {
      window.addEventListener('scroll',this.handleScroll)
    },
    deactivated(){
      window.removeEventListener('scroll',this.handleScroll)
    }
  }
</script>

<style lang="stylus" scoped>
  @import "~styles/varibles.styl";
  .header-abs
    position absolute
    left .2rem
    top: .2rem
    width .8rem
    height .8rem
    border-radius .4rem
    background: rgba(0, 0, 0, .8)
    text-align center
    line-height .8rem

    .header-abs-back
      color white
      font-size .4rem

  .header-fixed
    position fixed
    top 0
    left 0
    right 0
    height $headerHeight
    line-height $headerHeight
    text-align center
    color white
    font-size .32rem
    background $bgColor
    z-index 99

    .header-fixed-back
      position absolute
      top 0
      left 0
      width: .64rem
      text-align center
      font-size .4rem
      color white
</style>
